WELCOME TO THE VREDEFORT DOME

INFORMATION
SITE

The meteorite impact that
happened in the Free State made a crater that was about 300
km wide (from Johannesburg to Welkom!). This is the biggest
meteorite impact that geologists have yet found on Earth and
it is nearly twice as big as the impact that killed the
dinosaurs 65 million years ago. This makes it a site of
great importance for scientists. It is also the oldest
impact crater that has been found on Earth. It is mainly for
these reasons that it has been made a World Heritage Site.

Over many decades, geologists
from South Africa and other parts of the world have been
studying the broken and melted rocks around Parys and
Vredefort to understand this Vredefort Impact Even. This is
what they have found:

1. The meteorite impact
happened about 2023 million years ago, at a time when there
were no people or even animals of plants like we see today.
The only living thing was a type of algae, like the green
slime seen in dams today.

2. To make a crater 300 km
wide, the meteorite must have been about 10 km across (as
big as a mountain) and travelling at more than 10 km per
second (36 000 km/h!).

3. The Vredefort Dome is only
the central part of the impact crater. It is called a dome
because the rock layers were bent into the shape of an
upside-down bowl 90km across by the impact.

SHOOTING STARS AND METEORITE IMPACTS

If we look up into the sky on a
dark night we often see "shooting stars". These are bright
streaks of light that move very fast across the sky for only
a few seconds before they disappear. They are not real stars
- the streaks of light are caused by tine pieces of burning
rock, flying faster than bullets that enter Earth's
atmosphere from Outer Space. Because they are moving so fast
(more than 10 km per second, which means they would take 30
seconds to fly from Parys to Bloemfontein!), when they enter
the atmosphere they start to burn. (This burning is caused
by friction with the air. When you rub your hands together
very fast, they also get hot. To melt rock, though, the
temperature must reach more than 1000 °C!)

There are many, many millions
of such small pieces of rock in Outer Space, left over from
when our Sun and the planets were formed. Thousands of them
become shooting stars every day. But among them are also
larger pieces of rock, ranging from football size to some up
to many kilometers across. These asteroids also sometimes
fall into the Earth's atmosphere, but not as often as the
smaller pieces. When they do, they are too big to burn up or
slow down and so they hit the ground at very high speed. An
asteroid that hits the Earth is called a meteorite.
Thousands of small meteorites have already been found around
the world.)

The damage caused when a
meteorite collides with the Earth is massive. The speed of a
meteorite is so high that is explodes when intense heat of
many thousands of degrees Celsius that can even melt rock.
In this way, the meteorite itself is completely destroyed.
This is what happened in the Free State near Parys and
Vredefort millions of years ago. The explosion was so great
that it was many millions of times more powerful than the
biggest atomic bomb ever built on Earth. If it happened
today it would kill almost all living things on Earth,
including most people.